Rotary offset printing machine interrupter



April 3, 1951 E. J. JANKL ROTARY OFFSET PRINTING MACHINE INTERRUPTER 3Sheets-Sheet 1 Original Filed Jan. 17, 1945 Ill April 1951 E. J. JANKE2,547,471

ROTARY OFFSET PRINTING MACHINE INTERRUPTER Original Filed Jan. 1'7, 19453 Sheets-Sheet 2 J7 I o OFF I 70 7 :1 I 0 IN V EN TOR.

April 1951 E. J. JANKE 2,547,471

ROTARY OFFSET PRINTING MACHINE INTERRUPTER Original Filed Jan. 17, 19453 Sheets$heet 5 Patented Apr. 3, 1951 ROTARY OFFSET PRINTING MACHINEINTERRUPTER Edward J. Janke, Cleveland, Ohio, assignor toAddressograph-Multigraph Corporation, Cleveland, Ohio, a corporation ofDelaware Original application January 17, 1945, Serial No. 573,280.Divided and this application March 6, 1946, Serial No. 652,262

9 Claims.

This application is a division of my copending application No. 573,280filed January 17, 1945 for a Printing Machine.

The invention of this application relates to a rotary printing machineoperating on the planegraphic principle. The general object of theinvention is to provide such a machine which shall have means fortransferring an image from a master sheet to a transfer blanket in anenicient manner, and which shall reproduce on the transfer blanket animage corresponding accurately with the image on the master sheet, sothat an accurate impression will be made on the paper printed.

A more particular object of the invention is to control the approach ofthe master drum carrying the image to the offset drum carrying thetransfer blanket so that actual contact of the two drums shall start inadvance of the presentation of the image to the blanket, and thus theactual transfer of the image shall always be by rolling contact, therebyavoiding the smudging or distortion of the transferred image likely toresult from a radial or blow contact.

Still more particularly, my invention provides means for causing amaster drum to contact with the offset drum only when a gap in one ofthe drums faces the other drum.

The drawings illustrate a preferred embodiment of my invention. In thesedrawings, Fig. 1 is a vertical section through the machine, the offsetblanket being illustrated merely in conventional form; Fig. 2 is a sideelevation of 1atching mechanism for retaining the offset drum incoaction with the master drum and platen but allowing its immediateseparation from both such members, this view showing the drums in theirseparated or inactive position; Fig. 3 is a view of the same parts withthe latch in another position and the drums in their coacting position;Fig. 4 is a side elevation of certain parts of the machine outside ofthe right hand frame plate and in plane parallelwith Fig. 1; Fig. 5 is asection immediately broken away through the offset drum on a planeindicated by the line 5-5 on Fig. 1; Fig. 6 is a sectional elevation ona plane parallel with Figs. 1 and 4 showing some of the gearing employedin the machine.

I will first describe briefly the general characteristics of thecomplete printing machine indicated in the drawings.

In Fig. 5, there is shown two spaced vertical frame plates I0 and IIparallel with each other which together with bracing cross rods,constitute the main frame of the machine. Plate Ii] also appears in Fig.4 and the plate II in Figs. 1 and 6. Ordinarily these frame plates andthe machine carried thereby rest on a suitable base or stand indicatedat l5 in Fig. 1. This stand may house a driving motor I6 connected by abelt I! with a pulley I 8 of the printing machine.

The printing machine includes a master sheet carrying drum 20, an offsetdrum 3i} and a platen All all suitably mounted between the two plates I0and I I. Between these plates also is an inking mechanism 50 adapted todeliver ink to the master sheet 22 on the drum 2a, and a normally actingink repellent applying mechanism 60 acting on a region of the mastersheet in advance of the inking mechanism.

Between the frame plates Ill and II, there is also mounted the controlmechanism so for the manual paper feed and a projecting paper sup port91, and behind the platen there is provided means for holding aremovable receiving tray 98. Various mechanisms hereinafter describedare mounted on the exterior of the two frame plates Ii] and I I and areshielded by side cover plates I 2. Substantially all of the parts of themachine between the frame plates may be covered by a suitable coverwhich is removed when the machine is operated. Such removable cover isindicated at I9 as extending over the entire top of the ma-- chine anddownwardly beyond each end thereof to regions a short distance abovethepaper support and the inking fountain.

The master drum 20 is provided with an axially extending recess 23 inwhich is mounted an attaching means, generally indicated at 24, forattaching a printing plate'to the drum.

The master drum 253 is rigidly mounted on a shaft 2|, the ends of whichare preferably journalled in eccentric bushings 25 mounted in the frameplates I!) and II, to allow accurate alignment. The offset drum 30 isrotatably mounted on an eccentric central portion of a shaft 3I which ismounted in the two frame plates in a manner capable of a partialrotation, by which the position of the offset blanket 33 is adjustedwith reference to both the master sheet and the platen as hereinafterdescribed.

The platen 4!! is rotatably mounted on an eccentric intermediate portionof a shaft 4|, the axial end portions of which are mounted in bearingscarried by a yoke 42 pivoted to the plates I0 and I I at 63 and springpressed upwardly by a pair of spring units 45 (one of which is shown inFig. 1) which act against the transverse portion of the yoke distantfrom the pivot. These spring units maintain proper yielding pressurebetween 3 the platen and the offset cylinder during the operation of themachine.

Each unit 45 includes a spring #24 which bears at its lower end againsta fixed cross bar 55 carried by the two frame plates IE3 and I I. Attheir upper ends each spring acts against an adjustable stop 4'! on ascrew as, the upper end of which is anchored to the yoke and the lowerend of which. passes through the cross bar 45, and is provided with anut 49. These nuts provide adjustable limits for the upward movement ofthe platen yoke.

As shown, the inking mechanism 55: comprises a fountain 5! adapted tocontain ink. a fountain roller 52 therein, a swinging ductor roller 53,a longitudinally reciprocable distributing roller 55, and a form roller55. The latter coacts with the master sheet 22 on the drum 2%] and withthe distributing roll 54.

The form roll 55 may be manually separated from the master sheet 22 tofacilitate the initial application of ink-repellent thereto, as well asto facilitate the substitution of one master sheet for another. Asillustrated the form roll 55 is mounted between a pair of plates 55pivoted to the respective frame plates [0 and H and drawn by springs Eltoward the master sheet under the control of an adjustable stop screw53. A suitable cam rod 59 rotatively mounted in the frame plates isadapted to be turned by the operation of a hand lever 5911, Fig. 4, tocam the plates 56 in a direction to separate the form roll from thedrum.

The normal ink repellent applicator mechanism which acts on the mastersheet during each revolution of the master drum, as illustrated in Fig.1, comprises a trough 6! adapted to contain a liquid ink repellent, afountain roll 62 immersed therein, a swinging ductor roll 53 and anabsorbent form roll fi l. The form roll is mounted in a pair of pivotedend bars 65 which are drawn toward the master drum 20 by springs 66under the control of adjustable stop screws 51. The ductor roll 53oscillates between the fountain roll 52 and the form roll 64 to deliverrepellent to the master sheet.

The two ductor rolls 53 and 53, as well asthe fountain rolls 52 and 62,for the ink and repellent respectively are operated at the same time bya single cam 10 secured to the offset drum 30, which is driven bysuitable gearing as hereinafter explained. This cam Tl acts against aroller N (Fig. 4) on a lever 29 secured to a stub shaft 13 journalled inthe frame plate in. A second lever 12 is secured intermediate its endsto the stub shaft '53 and is connected by a link M- with mechanism notshown for periodically turning the ink fountain roll 52. The lever 12,also by mechanism not shown, actuates the repellent ductor.

The offset drum may be released from both the master drum and the platenby turning the eccentrio shaft 3! on which the offset drum is mounted.This shaft is normally in the position shown in Figs. 1 and 3. Asillustrated in Fig. 3, a cam 34 is secured to the shaft 3! and a spring39 is connected between this cam and the frame plate Hi to swing theshaft in a counter-clockwise direction and thereby move the offset drumaway from both the platen and the master drum. Normally the swinging ofthe shaft is prevented by a latch 3'! which is retained in engagementwith a tooth 36 on the cam by a spring 35.

The latch 31 has a suitable lateral extension 38 projecting through anopening in the cover on that side, so that whenever desired the latchmay be withdrawn from the cam 34 by manual pres- 4 sure against theextension 38. This releases the cam 34 and permits the spring 39 toswing the offset drum shaft and bring the offset drum to its inactiveposition, shown in Fig. 2. When it is desired to restore the offset drumto its active position, the operator grasps a handle or knob 32 which issecured to the shaft 3|, and turns the same in a clockwise directionuntil the cam 34 is reengaged by the latch 31. A portion of the handleis shown at 32 in Fig. 5, and it is indicated in broken lines in Fig. 4.

Coming now to the particular portion of the machine with which thepresent invention is concerned, I may repeat that it is an importantfeature of this invention that the master drum and the offset drum bebrought into position to contact with each other only at a time when agap in one of the drums is juxtaposed to the other drum, because thisavoids any blow or radial impact on the image, which might tend to blurthe reproduction. In the embodiment shown, the gap referred to is on themaster drum. By starting the coaction when the gap on the master drum isopposite the offset drum the image is never submitted to other pressurethan a rolling action.

The result above noted is accomplished by the mechanism shown in Figs. 2and 3. It will be there seen that the cam 34 is provided with a shoulderand pivoted to the frame plate I0 is a dog 5-! normally held in the pathof the shoulder by the spring 35. This spring, as heretofore stated,acts on the latch lever 3'! and is anchored at one end of that lever andat the other end to the dog 8! and tends to hold each of these members'against suitable stops secured to the frame plate. Mounted on the lever'12 is a pawl 82 normally held in the position shown in Fig. 2 by aspring M, which tends to retain a pin on the pawl against a portion ofthe lever 12.

The lever 72 is so timed with relation to the drums that it is swingingin counterclockwise direction whenthe gap of the master drum is passingthe blanket drum. In. the latter portion of this movement the pawl 82acts on the dog 8| and swings the lower end thereof out of the path ofthe shoulder 88, allowing the hand lever 32 to turn the eccentric shaftinto the position shown in Fig. 3, before the gap has passed theblanket, so that the blanket is in position to engage the master sheetas the rotation continues and brings the master sheet by rolling actioninto juxtaposition with the blanket.

In the operation of the machine, whenthe operator desires to cause theengagement of the master with the blanket he grasps the handle 32 andstarts to turn it in the clockwise direction. If the gap in the masterdrum happens to be opposite the blanket at this time the dog 8| willleave the cam free to move into position shown in Fig. 3. However,usually some other portion of the master sheet will be opposite theblanket when the operator starts to turn the handle 32 and hence theshoulder 80 will engage the dog 81 and the turning will be stoppedbefore the blanket is contacting with the master. The operator thencontinues his manual pressure in the clockwise direction, against theaction of the spring 39, until the dog BI is freed from the shoulder,whereupon the completion of the movement of the hand lever activelypositions the blanket ready to receive imprint of the image by rollingcontact. On the back stroke of the lever 12 the pawl 82 clicks idlyacross the end of the dog- 8!, as allowed by the spring 84.

It will be noted that the arrangement is such that the pawl will engagethe dog 8| for a relatively short period of time, quickly sliding fromthe end of the dog and permitting the dog to swing into the activeposition shown in Fig. 2, before the gap in the drum has passed thepoint of contact of the two drums.

In building up the image on the offset blanket, repellent is firstapplied to the master sheet and then ink applied, while the offsetblanket is held out of contact with the master sheet. Then the masterdrum may be rotated about four revolutions, retaining it still out ofcontact with the master sheet to build up the inked image on the mastersheet without further application of repellent. Then by rotating themaster drum about four more revolutions, with the ink and normalrepellent mechanism 5?} and 68 respectively in active engagement withthe master sheet, and with the offset blanket in contact with the mastersheet, a properly inked image will be produced on the offset blanket.These preliminary rotations of the master drum 2?) may be produced bypower, by turning the motor switch off and on, or by a hand wheelprovided on some member rotating with the drum. Such wheel is indicatedat 2? in Fig. 1 as being on the master drum shaft 2 I.

After the image has been properly built up on the blanket cylinder, andthe motor is running to drive the various parts, it is only necessary tofeed sheets to the bite of the blanket and platen drums to effectprinting. The sheetsto be printed are fed from the suitable tray 9?carried by the frame of the machine and projecting at the forward endthereof and adapted to carry a number of sheets with their edges fannedout so that they can be manually shoved one after another toward theprinting machine.

While the control of the sheet feed is no part of the invention of thisapplication, it is shown in Fig. 1, and may be briefly described asfollows: There is provided a lower feed roller NH, and a coacting upperroller I02. Each of these rollers is made in two longitudinally spacedsections mounted on suitable shafts. Behind the line of contact of thetwo feed rollers is a stop finger I83 mounted on a pivoted bar I04 andcounterweighted by a forwardly extending plate I515. The shaft of theupper feed roller I02 is journalled in a yoke frame I86 which is pivotedat It? and carries a roller I08 which coacts with a cam Iile secured tothe offset drum (Figs. 1 and 5). This cam for the most part isconcentric as shown in Figv 1 and by acting on the roller I88 maintainsthe upper feed roller out of contact with the lower feed roller andallows the counterweighted stop fingers to standin the position shown inFig. 1, thus preventing the shoving of the paper to printing position.

The paper is shoved forwardly manually during the period of separationof the upper andlower feed rollers under a suitable downwardly inclinedguide Ho until it abuts the fingers Hi3. Now when the flattened portionof the cam I89 comes opposite the roller IE8 this frees that roller andthe upper feed roller I02 descends by gravity into engagement with thelower feed roller. At the same time, a pin III depending from the frontportion of the pivoted yoke engages a lever I I2 on the bar let!carrying the stop fingers. This swings the stop fingers down to idleposition, out of the path of the sheet. The lowering of the upper feedroll not only removes the stop fingers from the path of the sheet butalso, because of the rotation of the lower feed roll, causes the sheetto be iii) fed forward between suitable guides into the bite of theoffset blanket and platen.

The paper feed rolls are held separated while the master sheet is beingprepared for the printing operation. To accomplish this use is made ofthe latch mechanism 34, 35, 36, 31 which is used to separate the olfsetand master drums during the period of preparation, as heretoforedescribed. A roller H5 is mounted on the yoke I36 which carries theupper feed r011 I92. When the offset drum shaft is in its idle position(Fig. 2) this roller is engaged by the cam 34 in such manner as to swingthe yoke I06 to raise the upper feed roll M2.

' The cam 34, it will be seen, performs three functions; it holds thefeed rollers separate when the drums are idle; it prevents thepositioning of the blanket drum except When the gap of the master drumis opposite it, and it retains the blanket drum in its active positionwhen it has been so placed until released by the actuation of the fingermember 38 on the latch 37.

While any suitable gearing may be used to rotate the various rotatableparts of the machine, I will, for completeness, describe the particulargearing so far as it app-ears in the drawings. As shown in Fig. 1 themotor I6 by its belt I'I operates a large sheave I8 which is on a shaftI26 rigidly carrying a pinion EZI. This pinion is shown as meshing withthe gear I22 on a stub shaft I23 carrying the pinion I28 (Fig. 6). Thepinion I28 meshes with a pinion I24, which meshes with a gear I25 on themaster drum 2B. The pinion I24 also is shown as meshing with a gear I27on the shaft of the distributing roll 54 of the inking systern.

The gear I25 on the master drum, which has a pitch circle correspondingto the periphery of the mounted master sheet, is shown as meshing withan equal size gear I36 (Fig. 6) on the offset drum. This latter gearmeshes with a gear I3I on the platen shaft 4|.

I claim:

1. In an offset printing machine including a frame having a master drumand a transfer drum, means to rotate said drums in timed relation witheach other, one of said drums being mounted for rotation on .a shafteccentrically mounted in the frame to move such drum into and out ofcontact with the other drum, means constantly tending to separate saiddrums, a latch normally acting to retain said drums in a contactingrelation and manually releasable at any time during the revolution ofthe drums whereby the drums may be separated at any time, manuallyoperated means to reset said drums in a contacting relation, meansincluding a latch plate on said shaft to cooperate with the latch,resilient means to hold the latch in a latching position, and a secondlatch to cooperate with the latch plate tolatch the shaft in a drumseparating position against the action of the resetting means, and meansoperating in timed relation with the rotation of the drum to releasesaid last named latch at a predetermined point in the revolution of themaster drum and hold the latch released for a predetermined portion ofthe cycle of revolution of the drum to thereby prevent resetting of saiddrums except during a predetermined portion of the cycle of revolutionof the master drum and yet permit separation of said drums at any timeduring the cycle of revolution of said drums.

2. An offset printing machine according to claim 1 having an armintegrally carried by the manually releasable latch and accessible tothe operator, a pair of spaced abutments' on the latchplate to engagerespective latches; resilient means tending to move the second namedlatch into the path of itsrespectiveabutment, an operating memberaccessible tothe operator manually operable to reset the drums andmounted on the eccentric shaft, aswingingar'moperating in timed relationwith the rotation of the drums, and a pawl carried onsaid arm to engagethe second named latch to move it out of engagement with its abutmentwhereupon the drums maybe reset manually.

3. An onset printing machine accordin to claim 2 having a Sheet feedingmechanism to feed sheets to be printed to the offset drum, and meanscarried by said latch plate and coacting. with said mechanism to causesaid mechanism to fa'ilto feed a sheet when the drums are separated.

4. An offset printing machine according to claim 3 wherein the sheetfeeding mechanism includes a pair of feed rolls, a pair of pivoted arms,one of said rolls being mounted in said arms for movement toward andfromthe other roll, means normally tending to hold said rolls in acoacting relation, and means carried by said arms and adapted to beengaged by said latchplate to separate said rolls when the drumsseparate.

5. In an offset printing machine including a frame having a master drumand a transfer drum, 2, platen, means to rotate said drums in timedrelation with each other, one of said drums being mounted for movementtoward and from the other drum whereby the drums may be brought intocontact with each other or separated, means constantly tending toseparate said drums, a manually releasable latch normally acting toretain said drums in a contacting relation, manually operable means toreset saiddrums in a contacting relation, releasable means to preventresetting of said drums, means to release said last named releasablemeans during a predetermined portion of the cycle of rotation of themaster drum and yet permit separation of said drums at any time duringthe cycle of revolution of said drums, consequent upon the release ofsaid releasable latch a pair of feed rolls to feed sheets to the bite ofsaid platen and offset drum, one of said rolls being movably mounted,means constantly tending to retain said rolls in a coacting relation,and means responsive to the movement of the movable drum to a separatedposition to move said movable roll away from its coacting roll.

6. In an offset printing machine, a frame having a master drum and atransfer drum and a platen roller, means to rotate said drums and rollerin timed relation with each other, said transfer drum being rotatablymounted on a shaft eccentrically journalled in said frame wherebyrotation of said shaft moves said transfer drum into and out of contactwith said master drum, a latch plate secured to said shaft, means tobias said shaft in a position with the transfer drum out of contact withthe master drum, a latch member coacting with said plate to oppose theaction of said biasing means and maintain said shaft in a position withthe drum in contact, said latch member bein manually releasable at anytime during the operation of said drums, a manually operable means onsaid shaft for turning said shaft against the action of said biasingmeans into cooperation with said latch, a second latch to engage saidlatch plate and restrain movement of said shaft by the opei anon (ifsaid manually operable means', means to bias-said" latches forengagement with said latch plate, a lever pivoted to said frame, means:to oscillate said lever once for each revolution of said drums, a pawlpivoted to said lever and adapted to: release said second named latchonly at .a predetermined point in therotative movement of said drums.

'7. A- printing machine according to claim 6- ha vihg apair'of coastingfeed rolls to feed sheets t'o the'bi teof said transfer drum and platefiroller, a pair of armspivoted to said frame intermediate their ends, oneof said rolls" being rotatably' mountedin said arms adjacent one e'n'dthereof and extending therebetween, a roller mounted on the opposite endof one of said arms and adapted to engage the periphery of saidlatchplate, andwherein said latch plate is provided with acam portion toengage said-roller and move said arms to separate said feed rolls whenthe cam plate moves out of engagement withsaid first named latch.

8. In an offset printing machine, a frame having a master drum and atransfer drum, means to rot'ate said drum in timed relation with eachother, said transfer drum being rotatably mounted ona shafteccentrically journalled in the frame to move said transfer drum intoandout of contact with said master drum, a latch plate secured to saidshaft, resilient means interposed between said plate and frame to biassaid shaft toa position with the transfer drum out of contact with themaster drum, a latch manually releasable at any time during therevolution of said drums, said latch member being pivoted to said frameand coacting with said plate to retain said plate and shaft in positionwith the transfer drum in contact with the master drum, manuallyoperable means on said shaft for turning said shaft against the actionof said spring and into cooperation with said latch, a second latchpivoted to said frame and coacting with said latch plate to restrainoperation of said manu-- ally' operable means, resilient meansinterconnecting said latches to bias them for engagement with said latchplate, a lever pivoted to said frame, means to oscillate said lever oncefor each revolution of said drums, apawl pivoted tosaid lever andadapted to swing said second named latch momentarily to a releasedposition at a predetermined point in the rotative movement of saiddrums.

9. In an offset printing machine, a frame having a master drum having aprinting plate posi tioned on a portion of its periphery and having aportion of its periphery extending substantially from end to end thereofuncovered by said printing plate, a transfer drum and a platen rollertogether with means to rotate said drums and roller in timed relationwith each other, said transfer drum being rotatably mounted on a shafteceentrically journalled in the frame whereby rotation of said. shaftmoves said transfer drum into and outof contact with said master drum, amember secured to said shaft, a spring interposed between said memberand said frame to bias saidshaft for movement to a position with thetransfer drumout of contact with the master drum, a manually releasablelatch pivoted to said frame and engaging said member plate to retainsaid shaft in a position with the transfer drum in contact with themaster drum, said latch being manually releasable at any time during therotation of said" drums, manually operable means for turning said shaftagainst the action of said spring and said member into latchingengagement with said latch, a second releasable latch pivoted to saidframe and adapted to engage said member and prevent movement of saidshaft by preventing the operation of. said manually operable means,resilient means to bias said latches for engagement with said member, alever pivoted to said frame, means carried by one of said drums to swingsaid lever back and forth once during each revolution of said drums, andmeans on said lever to momentarily move said second named latchmomentarily to a released position only when the uncovered portion ofthe master drum is in position to coact 15 with the transfer drum.

EDWARD J. JANKE.

10 Q REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS

